The quinoline compound represented by formula (3) is disclosed in JP-A-1-279866, EP-A-304063 and U.S. Pat. No. 5,011,930 as a useful cholesterol reducing agent (HMG-CoA reductase inhibitor), and the 2-aminobenzophenone represented by formula (2) (wherein X=4-F) is reported to be useful as its intermediate in Tetrahedron Letters, 1993, vol. 34, p.8267. ##STR2##
Likewise, the mental disorder agent represented by formula (4) and the anti-inflammatory agent represented by formula (5) are also synthesized via 2-aminobenzophenones. Therefore, establishment of an industrially advantageous process for their production is of great significance. ##STR3##
Some processes have been reported for production of 2-aminobenzophenones [review: Synthesis, 677 (1980)]. The process using anthranilic acid as the starting material which comprises formation of an acid chloride after protection of the amino group by a tosyl group and the Friedel-Crafts reaction followed by deprotection has been known long (Org. Synth. Coll. Vol. IV, 34 (1963), Scheme 1) and appreciated for the low raw material cost and the reliability. However, because of the use of concentrated sulfuric acid as the solvent essential for the last detosylation step, the process admittedly has a serious problem with waste liquor disposal from the industrial aspect. Conversely, this means that the production route is pretty fine only if this problem is solved. ##STR4##
wherein X is a hydrogen atom, a C.sub.1-4 alkyl group or a halogen atom.